Death Domain (DD) of the human protein ankyrin-3 (ANK-3) and related proteins. Ankyrins are modular proteins comprising three conserved domains, an N-terminal membrane-binding domain containing ANK repeats, a spectrin-binding domain and a C-terminal DD. ANK-3, also called anykyrin-G (for general or giant), is found in neurons and at least one splice variant has been shown to be essential for propagation of action potentials as a binding partner to neurofascin and voltage-gated sodium channels. It is required for maintaining axo-dendritic polarity, and may be a genetic risk factor associated with bipolar disorder. ANK-3 may also play roles in other cell types. Mutations affecting ANK-3 pathways for Na channel localization are associated with Brugada syndrome, a potentially fatal arrythmia. In general, DDs are protein-protein interaction domains found in a variety of domain architectures. Their common feature is that they form homodimers by self-association or heterodimers by associating with other members of the DD superfamily including CARD (Caspase activation and recruitment domain), DED (Death Effector Domain), and PYRIN. They serve as adaptors in signaling pathways and can recruit other proteins into signaling complexes.